1. Field of the Invention
The present invention relates to a metal vessel having a circumferential side seam formed by lap bonding and a process for the production of this metal vessel. More particularly, the present invention relates to a metal vessel, especially in the form of a bottle, which is highly improved in the adhesion, sealing property and corrosion resistance of the seam, and a process for the production of this metal vessel.
2. Description of the Prior Art
In conventional metal cans, sealing between a can body member and a can lid member is mainly accomplished by double seaming of both the members. More specifically, in case of a can body member having a side seam, for example, that of a three-piece can, top and bottom lids are double-seamed to the can body member, and in case of a can body member having no seam between the can bottom and side wall, which is formed by draw forming or draw-ironing forming, for example, that of a two-piece can, one can lid is double-seamed to the open end portion of the can body member.
However, when sealing of a plurality of members constituting a can is accomplished by double seaming, various defects arise. In the first place, the sealed portion formed by double seaming is poor in pressure resistance and impact resistance. In the second place, the material to be used is limited because double seaming is carried out. In the bonding method utilizing the double-seaming operation, the material constituting the seam is first deformed by pressure or shock applied to the seam, and peeling of the sealant, leakage at the seam or destruction of the seam per se is readily caused. In case of metal cans, it is always required to decrease the cost of the metal material necessary for production of can bodies by reducing the thickness of the side wall portion and decreasing the weight per unit volume. However, if the side wall portion of a can body is reduced, the buckling strength should naturally be reduced. When a can lid is double-seamed to a can body, the axial load to be applied to the can body by a double seamer is 120 to 200 Kg, and if the thickness of the side wall portion is reduced below a certain limit, double-seaming of a can lid becomes difficult.
In view of the foregoing, bonding of a plurality of members constituting a metal vessel through a circumferential side seam is not preferred from the viewpoint of the pressure resistance or impact resistance or in order to reduce the thickness of the material.